Oxygen is an allotropic element, with the most common form of the gas being the diatomic form (0.sub.2). Ozone (0.sub.3) and singlet oxygen (.sup.1 0.sub.2) are other forms of the gas that occur naturally and that can be created artificially. Ozone is the triatomic form of oxygen and is relatively unstable. Several methods of forming ozone are well known.
The benefits of ozone gas molecules (0.sub.3) are well known in the medical community for treatment of blood and human tissue in order to fight disease or other pathogens, or at least to ameliorate the effects thereof. Many diseases have been shown to be positively effected through the administration of ozone. Ozone has been found to kill cancer cells, be effective against various viruses and fungi, and to inactivate a wide variety of bacteria including pseudomonas aeruginosa, staphylococcus aureus and mycobaterium tuberculosis. Ozone has also been found to have disruptive effects on malignant tumour cells. The administration of ozone is also known to have beneficial effects to a patient's health in general by way of stimulating oxygen metabolism. It has also been shown that the administration of ozone and singlet oxygen to a healthy patient, through direct inhalation, can help prevent various diseases, such as those discussed above.
The introduction of too much ozone into the human body is not desirable, however. It is therefore very important to be able to regulate the concentration of ozone in an aliquot of blood, or other carrier liquid, that is being administered to a patient. In order to properly and accurately regulate the concentration of ozone in an aliquot of blood, it is necessary to be able to accurately control the amount of ozone introduced into the aliquot of blood, and therefore accurately regulate the amount of ozone generated by the ozone generator being used.
An electrode type ozone generator typically has a pair of electrodes separated by a suitable gap, with the 0.sub.2 gas that is to be ozonated passed along this gap between the electrodes. High potential voltage pulses are introduced across the electrodes in order to cause small sparks of electricity to jump between the electrodes and thereby excite the electrons of the 0.sub.2 molecules, and thus cause ozone molecules to be created. The small sparks of electricity form a visible corona around and between the electrodes.
One method known in the prior art that is used to attempt to control the mount of ozone generated by an ozone generator is the regulation of the voltage across the electrodes of the ozone generator. Unfortunately, it has been found that electronically varying the AC high voltage across the electrodes is difficult to do in an accurate manner. Typically, triacs are used to drive the electrodes. It is not possible to vary the phase angle to the gate of such triacs in small increments in an accurate manner.
Another method that is used to control the amount of ozone production of a corona discharge type ozone generator is to vary the frequency of the voltage pulses applied to the electrodes. This method is slightly more accurate than regulation of the voltage across the electrodes, however, this method offers a very limited range because of the frequency characteristics of the circuitry supplying the voltage pulses to the electrodes. The components in such circuitry generally must be chosen to construct a circuit to operate at a predetermined frequency. Resultingly, the pulses that are generated and sent to the electrodes are not properly produced outside a limited frequency range around this predetermined frequency and correspondingly ozone production tends to drop off considerably outside of this range. Varying the frequency of the pulses applied to the electrodes therefore works only over a small frequency range, which corresponds to a small range in change of ozone production that is possible.
It is also possible to vary the flow of oxygen gas molecules (0.sub.2) into an ozone generator by way of opening or closing a valve, with the flow of oxygen gas molecules through the valve being indicated by a flow meter. However, due to inherent inaccuracy of flow meters, this method does not provide for an accurate way of controlling ozone production. Further, only a limited range of adjustment is possible since for many applications, low pressures of oxygen are used.
Therefore, it is not known how to accurately regulate the amount of ozone generated by an electrode type ozone generator.